Spinner for model airplane propellers



April 6, 1954 R. A. lRwm 2,874,o63

SPINNER FOR MODEL AIRPLANE PROPELLERS Filed March 4, 1952 Hay/770314 Patentecl Apr. 6, [954 UNITED S'TATES PATENT OFFICE i 2,674,063 SPINER FORVMOD'EL AI'RPLA'NE PROPELLER'S Raymond Irwin, Manitowoc, Wi's., ;assignor to Kaysun Incorporated, Manitowoc, Wis., a corporaton of Wisconsin ApplicationMarch'l, 1952, Serial No.V 274,753

4 Claims'. (Cl. 46-78) This invention relates vgenerally to model airplane propellers and refers more particularly to an improved spinner 'for installation on the hub portion thereof.

Heretofore model airplane propeller spinners have had to be formed integrally with the propeller or else have had to be secured to the propeller by means of a fastening, such as a screw or pin, or by means of an adhesive. On small rubber-powered model aircraft particularly, it was necessary to cement the spinner to the propeller in order to hold it in place thereon, but this expedient was unsatisfactory because it prevented ready access to the propeller shaft and also because it virtually prevented re-use of the spinner on aV diiferent propeller.

It is therefore an object of this invention to provide an extremely light, simple and attractive spinner for model airplane propellers which spinner can be readily installed without the use of tools and will remain securely in place on the hub portion -of the ,propeller without extraneous fastening means and in 'a 'manner allowing the same to be readil'y detachable from the propeller whenever desired.

With the above and other objects in view, which will appear as the description .proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being un- I de'rs'to'od that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawing illustrates one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a side elevational view of the nose portion of a model airplane having the spinner of this invention installed on the propeller;

Figure 2 is a perspective view of the spinner of this invention;

Figure 3 is a view similar to Figure 2 but showing a propeller in the process of being installed in the spinner; and

Figure 4 is a cross sectional view through the propeller blade taken on the plane of the line 4-4 in Figure 1 and illustrating particularly the manner in which the spinner grips the roots of the propeller blades when mounted on the propeller.

Referring now more particularly to the accom- ,panying drawing. the numeral 5 designates gener'ally the nosezp'ortion of a model airplane-having a propeller B driven by a rubber band motor, not shown, one end of which is attached to a propeller shaft 1 which is turn secured in the hub portion 8 of the propeller. shaft extends through an -axial bore in the propeller and is bent over at its front end as at 9 to provide a. secure connection through which the tc-rque of the rubber band may 'be transm-itted to the propeller. i

Since the bent over portion of the hook does not present a particularly attractive appearance, and since the hub portion of the propeller isnot eiiicient aerodynamically, it is desira'ble .torcover the same with -a substantially con'ical spinner HI, both to improve its appearan'ce and to streamline it. The spinner of this invention comprises a hollow conical or cup-'sh'a'ped 'shell molded of a suitable plastic and open 'at its rear. A pair of diametrically opposit'e elong'at'ed slots ll extend forwardly from the edge |2 at 'the r'ear of 'the shell. The mouths l3 of th'evsl'ots are substantially narrower than their botto'm portions |4, and as may be seen from Figure 4 the slots substantially conform in shape to the cross-section or pro'file 'of the root portions |6 of the propeller blades, and are correspondingly disposed at an angle to 'the edge l2. The spinner is. held in place upon the vpropeller by reason of the fact that the root portions of the propeller blades are snugly seated `in the slots. VSince the blades are inserted edgewise into the slots 'during installation, and since the leading edges of the blades are substantially thicker than their trailing edges, insertion of the blades into the spinner' slots necessitates some displacement out of their normal positions of the wall portions |5 o-f the spinner which lie between the slots and the rim |2 of the spinner. To facilitate such deformation the wall portions |5 taper in thickness and are thinnest at the mouths of the slots. Since the plastic of which the spinner is formed is flexible and resilient, these wall portions will immediately resume their normal positions after the blades of the propeller are seated in the slots.

Although the outline of each slot in the spinner substanti'ally conforms to the contour of the propeller blade root, it need not accurately correspond thereto as long as the rear edge |1 of the notch engages the 'blade at one or more points, as shown in Figure 4, to thereby prevent the blade from slipping out of .the slot. Moreover, if the slot is somewhat undersize, the flexibility of the wall portion |=5 will nevertheless enable the spinner to have a reasonably good nt The propeller.

on the propelier; and indeed, it increases the security with which the spinner is held in place. The slots may lof course be enlarged Slightly, without undue diificulty, to aocommodate an excessively thick propeller blade root.

Although the spinner of this invention very securely remains in place upon the propeller it may nevertheless be readily removed by edgewise withdrawal of the propeller blade roots therefrom, using a twisting motion opposite to that employed in installing the spinner, the wall portions |-5 again fiexing to facilitate such withdrawal.

From the foregoing description taken together with the accompanying drawing, it will be readily apparent that this invention provides a light and attractive spinner for model airplane propellers which may be installed without the necessity for cement, or other extraneous fastening means, and which will remain securely in place upon the propeller but which will nevertheless be readily removable therefrom.

What I clairn 'as my invention is:

1. A Spinner for model airplane propellers comprising: a hollow substantially conical shell of flexible material open at its rear and of a size to receive the hub of a propeller on which the Spinner is to be installed, the wall of said shell 'having inclined slots opening to its edge and extending forwardly therefrom at an acute angle therein, which slots are narrower at their mouths -than at their bottom portions and are shaped to substantially correspond to the pi'ofile of the root of a propeller blade, the wall portion of the shell in the triangular area defined by the rear edge of the spinner and the adjacent edge of each inclined slot being thinner than the remainder thereof to permit said wall portions to be resiliently displaced fiatwise from their normal positions so that propeller bla-des may be inserted edgewise into the slots without necessitating disassembly of the blades from the propeller hub.

,2. A Spinner for model airplanes comprising: a hollow substantially conical shell open at its large di'ameter rear end of a size to accommodate the hub portion of a propeller,` said spinner being characterized by the fact that it is made of flexible material and further Kcharacterized by elongated inclined slots opening to its rear edge and extending forwardly therefrom at an acute angle thereto, said slots being narrower at their months 4 'than at their bcttom portions and shaped to substantially correspond to the profile of the root of a propeller blade to enable installation of the spinner upon the hub portion of a propeller by edgewise insertion of the propeller blades into the slots, the fiexibility of the material in the triangular area defined by the rear edge of the shell and the adjacent edge of each inclined slot enabling the thick leading edge portion of the blade to be passed through the narrow mouth of :the slot by permitting flatwise displacement of said 'area away from the spinner axis.

3. The Spinner of claim 2 further characterized by the fact that the wall portion of the spinner in said triangular area is tapered in thickness toward the mouth of the slot to facilil`tate fiexing of said portions of the shell w'all out of their normal positions during installation of the Spinner upon the propeller.

4. A 'Spinner for model airplanes comprising a substantially conical shell having a large coaxial well therein opening to its large di'ameter rear end to accommodate the hub portion of a propeller and to define a rim at the rear of the Spinner, which rim lies in a plane normal to the Spinner axis, said spinner being characterized by inclined slots opening to said rim and shaped to substantially conform to the profile of the roots of the blades of a propeller on which the Spinner is to 'be installed, said slots being substantially narrower at their mouths than at their` .bottom portions and extending forwardly at an acute angle to said rim; and further characterized by the fact that the ti'iangular Wall portions of the-spinner between said rim and the adj'acent edge of each slot are resiliently deformable flatwise from their normal po-sitions to accommodate the thick front portion of the propeller blade roots during edgewise insertion of the blade roots into the slots.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date l,'723,446 Schutte Aug. 6, 1929 2,042,715 Hunt June 2, 1936 2,131,490 Walker Sept. 27, 1938 2,528,494 i Brookshier V Nov. 7,1950 2,559,882 Lanier July 10, 1951 2,601,742 Kusold July 1, 1952 

